This invention relates to a fitting for mounting to the ends of smooth wall tubes, particularly, expanded end tubes and beaded or barbed end tubes.
The fitting of the present invention is generally relates to those types of fittings disclosed in U.S. Pat. Nos. 3,738,688; 3,779,587; 3,868,132; and 4,154,465.
The fittings disclosed in some of the above-mentioned U.S. patents are mounted to the end of a smooth wall tube by, generally, compressing a seal against the outer diameter of the tube upon translation of a ram element within the housing thereof. Others of these fittings grip on the outside diameter of the tube and also seal on the inside diameter. While these fittings function exceptionally well in most cases, difficulties may be encountered in affixing these fittings to expanded end tubes and beaded or barbed end tubes. The fittings of the present invention are specifically designed for use with tubes of these latter described types. In particular, in the case of expanded end tubes, the fitting is designed to grip behind the expansion and to seal on the tube outer diameter. The fitting thus is securely affixed to the tube such as to allow for full flow of fluid when charging or evacuating compressor tubing or expanded end headers on condensor or evaporator systems. In the case of beaded end tubes, the fittings provide maximum safety characteristics through gripping behind the beaded section of the tubes with sealing on the outside tube diameter. In the case of barbed end tubes, the fittings grip behind and between the barbed section of the tubes. In each case also, the fittings have a pressure assist design that furnishes increased sealing and gripping action with increase in sealing pressure. The fittings, furthermore, will accept wide variations in expanded end lengths and lengths from bead or barb to the end of the tube.
Accordingly, it is an object of the present invention to provide improved fittings for mounting to the ends of smooth wall tubes, particularly smooth wall tubes of the expanded end, beaded and barbed type.